The Box is a container of many stars representing realities.
The image of The Box was taken using the Fungal Projector, which dissolves space into an object with various properties related to the old space.
It contains many blue "stars" when viewed this way, each of which radiate various amounts of dimensions. The most common amounts are 1024, w, w2, w^2, etc. These stars are unfathomably huge, with each one containing a unique reality, with all of its -verses and other entities. The center of these stars are the top of said dimensions.
In between these "stars" is a massive, incomprehensible void called the Metaempiric Space. Next to nothing can survive in it for long and serves as a barrier to keep realities from merging. It is truly empty, with absolutely nothing real or unreal existing in it.